1. Field of the Invention
The present invention relates to a device adapted to retain in position fastening screws on a member or part adapted to be secured by means of said screws.
2. Description of the Prior Art
Many captive screw devices of this type have already been proposed. A number of them are illustrated in the "Machine Design" Nov. 10, 1960 issue (page 181). The Dutch patent No. 128,844 also discloses a device adapted to retain in position a screw on a part or member, before utilizing this screw for fastening the part or member to another structure or member.
The use of captive screw devices of this type enables manufacturers of a given article to dispose beforehand the number of screws necessary for the subsequent fastening of this article. Thus, this last or fastening operation is greatly facilitated since the final user is not compelled to care for the necessary fastening screws, and for the positioning of these screws in the corresponding holes of the article to be fastened. Therefore, the use of such screw retaining devices on a growing number of articles such as electrical apparatus, some sanitary articles and also ski bindings is becoming increasingly popular.
However, it should be noted that many screw retaining devices now in current use comprise an element which remains subsequently interposed between the part to be fastened and its support. This is observed notably in the case of the device disclosed in the abovementioned Dutch patent No. 128,844. In fact, this device comprises essentially a plastic washer in which the screw to be retained in position is retained by screw engagement. Now, this washer comprises an external flange engaging the surface of the corresponding member opposite the surface registering with the screw head. When fastening this member, this flange remains interposed between the member and its support, and this may constitute an inconvenience in many cases.
To avoid this inconvenience, a known proposal consisted in providing corresponding recesses in the corresponding member or part for disposing the retaining support or device associated with each screw therein. However, this solution is also objectionable in that these special recesses have to be formed within the member or part to be fastened, and that each retaining support has to be positioned in the relevant recess. This obviously entails a substantial increment in the cost of the articles or parts thus prepared.